JP2610840B2 - Method for producing propylene copolymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a propylene copolymer. More specifically, the present invention provides for the polymerization of propylene or a propylene / ethylene mixture in at least two steps in the presence of a particular catalyst to produce a propylene copolymer,
In particular, it relates to a method for producing a propylene block copolymer.

According to the method of the present invention, a propylene copolymer having high rigidity, high impact strength and good fluidity can be produced with high activity and low by-product of low crystalline components.

Prior Art As a method for improving the impact strength of crystalline polypropylene having excellent properties of rigidity and heat resistance, particularly, the impact strength at low temperatures, propylene and ethylene or other olefins are polymerized stepwise to block. A method for producing a copolymer is already known (JP-B-43-11230).
Nos. 44-16668, 44-20621, 49-24593, 49
No. -30264, JP-A-48-25781, JP-A-50-115296, JP-A-53-35
Nos. 789, 54-110072, etc.).

However, when propylene and ethylene are polymerized in two or more stages, the impact resistance is improved, but a low-crystalline polymer by-produced in large quantities due to the inclusion of the copolymerized portion, and the polymer particles produced However, it has an industrial problem such that it becomes sticky and causes operation trouble due to adhesion of polymer particles. Therefore, many attempts have been made to reduce by-product low-crystalline components.

On the other hand, a titanium trichloride type catalyst is well known as an olefin stereoregularity catalyst, but since it has a low activity, a detouching step is required.

A technique for introducing a magnesium compound into a solid catalyst component in order to improve the activity until non-contact is possible is well known. Further, a technique of using an electron donor as a solid catalyst component or a polymerization additive in order to suppress these by-product low crystallinity components is also well known (Japanese Patent Application Laid-Open Nos. 47-9842 and 50-126590).
No. 51-57789, etc.).

Then, a method for producing a propylene block copolymer using these catalyst systems has been proposed (JP-A-52-98045, JP-A-53-88049, etc.). However, these methods are still unsatisfactory in practical use since many low-crystalline components are by-produced.

Furthermore, to improve this, as a polymerization additive, Si
A method using an organosilicon compound having a -OC or Si-ON bond and a method using a fourth additive have been proposed (JP-A-58-83016 and JP-A-61-69823). etc). However, this method has the following problems because the molecular weight of the rubber portion or the polyethylene portion, which is an ethylene / propylene copolymer, is small.

(1) The produced rubber is easily extracted from the polymer, which becomes a low-crystalline component as a by-product, and the produced polymer is sticky, causing the polymer to aggregate, stick, etc., resulting in an operation trouble.

(2) The low-temperature impact resistance is not improved.

(3) In order to maintain the MFR of the entire polymer, it is necessary to increase the molecular weight of the crystalline polypropylene portion, and therefore, the spiral flow, that is, the flowability of the polymer in the mold is deteriorated.

SUMMARY OF THE INVENTION The present invention provides a method for producing a propylene copolymer, which comprises performing the following steps in the presence of the following catalyst.

Catalyst A catalyst obtained by combining the following components (A), (B) and (C): Component (A) Component (i): a solid component containing tetravalent titanium, magnesium and halogen as essential components, and a component (ii): general formula _{^{R 1 R 2 3- nSi (oR}} 3) n ( where the R ¹ is a branched hydrocarbon residue, the R ² is R ¹ identical or different hydrocarbon residues, R ³ is a hydrocarbon residue, n is 1 ≦ n ≦
A solid catalyst component obtained by contacting: a silicon compound represented by the following formula (3), a component (B) an organoaluminum compound, a component (C) a general formula M (OR ⁴ ) x R ⁵ yXz (where M is B, Al, C, S
An element selected from the group consisting of i, P, Ti and Zr is represented by R ⁴
And R ⁵ are the same or different hydrocarbon residues having 1 to 20 carbon atoms, X is a halogen atom, x is a number greater than 1 and equal to or less than the valence of the M element, and x + y + z is an atom of the M element A step of producing a propylene copolymer having a total ethylene content of 3 to 40% by weight, comprising the following steps (1) and (2): step (1) propylene alone Or a propylene / ethylene mixture having an ethylene content of 5% by weight or less, in one or more stages, to form a polymer in an amount corresponding to 60 to 95% by weight of the total polymerization amount. Propylene equivalent to 100% by weight /
A step of polymerizing the ethylene mixture in one or more stages.

According to the method of the present invention, the molecular weight of the propylene / ethylene copolymer part and / or the polyethylene part is increased by suppressing the by-product of the highly active and low crystalline component, that is, high rigidity and high rigidity are achieved. A propylene copolymer having an impact strength, in particular, a propylene / ethylene block copolymer can be produced.

In addition, since the obtained copolymer powder has no stickiness, an operation trouble due to agglomeration and sticking of the copolymer powder can be solved.

In the method of the present invention, the catalyst used has excellent activity continuity, so that the catalyst can be easily operated without a decrease in catalytic activity in the latter half of a long-time operation, particularly when performing multistage polymerization.

Furthermore, since the molecular weight of the crystalline polypropylene part in the obtained copolymer can be reduced, the fluidity (for example, spiral flow) of the product polymer is improved.
Further, in the present invention, since the catalyst system is simple, it is easy to control the target product performance.

DETAILED DESCRIPTION OF THE INVENTION Catalyst The catalyst used in the method of the present invention is a combination of the following components (A), (B) and (C).

Component (A) Component (A) of the catalyst used in the present invention is a solid catalyst component obtained by contacting the following components (i) and (ii).

Component (i): a solid component containing tetravalent titanium, magnesium and halogen as essential components.

Component (ii): General formula R ¹ R ² _3- nSi (OR ³ ) n (where R ¹ is a branched hydrocarbon residue, R ² is a hydrocarbon residue which is the same as or different from R ¹ , R ³ is a hydrocarbon residue, n is 1 ≦ n ≦
The silicon compound is represented by the following formula:

The solid component containing titanium, magnesium and halogen used as the component (i) as essential components is a known solid component. For example, JP-A-53-45688, 54-3894
No. 54-31092, No. 54-39483, No. 54-94591, No. 54
-118484, 54-131589, 55-75411, 55-90510
No. 55-90511, No. 55-127405, No. 55-147507, No.
55-155003, 56-18609, 56-70005, 56-7200
No. 1, 56-86905, 56-90807, 56-155206,
57-3803, 57-34103, 57-92007, 57-121003
No. 58-5309, No. 58-5310, No. 58-5311, No. 58-87
No. 06, No. 58-27732, No. 58-32604, No. 58-32605, No.
58-67703, 58-117206, 58-127708, 58-183
Nos. 708, 58-183709, 59-149905 and 59-149906 are used.

As the magnesium compound serving as a magnesium source of the catalyst used in the present invention, magnesium halide, dialkoxymagnesium, alkoxymagnesium halide, magnesium oxyhalide, dialkylmagnesium, magnesium oxide, magnesium hydroxide,
And magnesium carboxylate.

The titanium compound serving as a titanium source is represented by the general formula Ti (OR
⁶ ) _4- nXn (where R ⁶ is a hydrocarbon residue, preferably having about 1 to 10 carbon atoms, X represents halogen,
n shows the number of 0 <= n <= 4. )). Specific examples include TiCl ₄ , TiBr ₄ , Ti (OC
_{2 H 5) Cl, Ti (} OC 2 H 5) 2 Cl 2, Ti (OC 2 H 5) 3 Cl, Ti (O-
nC ₃ H ₇ ) Cl ₃ , Ti (O-nC ₄ H ₉ ) Cl ₃ , Ti (O-nC ₄ H ₉ ) ₂ Cl
_{2, Ti (OC 2 H 5} ) Br 3, Ti (OC 2 H 5) (OC 4 H 9) 2 Cl, Ti (O
_{-NC 4 H 9) 3 Cl,} Ti (O-C 6 H 5) Cl, Ti (O-iC 4 H 9) 2 Cl
_{2, Ti (OC 5 H 11} ) Cl 3, Ti (OC 6 H 13) Cl 3, Ti (OC
_{2 H 5) 4, Ti (} O-nC 3 H 7) 4, Ti (O-nC 4 H 9) 4, Ti
_{(O-iC 4 H 9)} 4, Ti (O-nC 6 H 13) 4, Ti (O-nC 3 H
₁₇ ) ₄ , Ti [OCH ₂ CH (C ₂ H ₅ ) C ₄ H ₉ ] _{4 and the} like. Among them, TiCl ₄ is particularly preferable.

Further, a molecular compound obtained by reacting an electron donor described later with TiX ′ ₄ (where X ′ represents halogen) can also be used. Specific examples include TiCl ₄ .CH ₃ COC ₂ H ₅ , TiCl ₄ .C
H ₃ CO ₂ C ₂ H ₅ , TiCl ₄・ C ₆ H ₅ NO ₂ , TiCl ₄・ CH ₃ COCl, TiCl ₄・
C ₆ H ₅ COCl, TiCl ₄・ C ₆ H ₅ CO ₂ C ₂ H ₅ , TiCl ₄・ ClCOC ₂ H ₅ , TiC
l ₄ · C ₄ H ₄ O and the like.

The halogen source is usually supplied from the above-mentioned halogen compound of magnesium and / or titanium, but is supplied from a known halogenating agent such as a halide of aluminum, a halide of silicon, and a halide of phosphorus. You can also.

The halogen contained in the catalyst component may be fluorine, chlorine, bromine, iodine or a mixture thereof, with chlorine being particularly preferred.

The solid component used in the present invention includes SiCl
_4, CH ₃ SiCl _3, silicon compounds such as methylhydrodiene _{polysiloxane, Al (OisoC 3 H 8)} 3, AlCl 3, AlBr 3, Al
Aluminum compounds such as (OC ₂ H ₅ ) ₃ and Al (OCH ₃ ) ₂ Cl and boron compounds such as B (OCH ₃ ) ₃ , B (OC ₂ H ₅ ) ₃ and B (OC ₆ H ₅ ) ₃ Other components may be used, which may remain in the solid component as components such as silicon, aluminum and boron.

Further, when the solid component is produced, it can be produced by using an electron donor as an internal donor.

Examples of electron donors (internal donors) that can be used for producing the solid component include alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic acids or inorganic acids, ethers, acid amides, and acids. Examples include oxygen-containing electron donors such as anhydrides, and nitrogen-containing electron donors such as ammonia, amines, nitriles, and isocyanates.

More specifically, methanol, ethanol, propanol, pentanol, hexanol, octanol, dodecanol, octadecyl alcohol, benzyl alcohol, phenylethyl alcohol, cumyl alcohol,
C 1 -C such as isopropylbenzyl alcohol
18 alcohols; phenols having 6 to 25 carbon atoms which may have an alkyl group, such as phenol, cresol, xylenol, ethyl phenol, propyl phenol, cumyl phenol, nonyl phenol, and naphthol;
C3 to C15 ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone and benzophenone; C2 to C15 such as acetaldehyde, propionaldehyde, octylaldehyde, benzaldehyde, tolualdehyde and naphthaldehyde
Aldehydes: methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valerate, ethyl stearate, methyl chloroacetate, ethyl dichloroacetate, methacrylic acid Methyl, ethyl crotonate, ethyl cyclohexanecarboxylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, methyl toluate,
Ethyl toluate, amyl toluate, ethyl ethyl benzoate, methyl anisate, ethyl anisate, ethyl ethoxy benzoate, diethyl phthalate, dibutyl phthalate,
Organic acid esters having 2 to 20 carbon atoms such as diheptyl phthalate, γ-butyrolactone, α-valerolactone, coumarin, phthalide, ethylene carbonate, etc .; borate esters such as triethyl borate and triphenyl borate; triethyl phosphite; Phosphites such as trioctyl phosphite; phosphoric esters such as tributyl phosphate, triphenyl phosphate and diethyl phenyl phosphate; inorganic acids such as silicate esters such as ethyl silicate, butyl silicate and phenyltriethoxysilane Esters; C2 to C15 acid halides such as acetyl chloride, benzoyl chloride, toluic acid chloride, anisic acid chloride, phthaloyl chloride, phthaloyl isochloride; methyl ether, ethyl ether, isopropyl ether, butyl ether, aluminum ether Tetrahydrofuran, anisole, ethers having 2 to carbon atoms, such as diphenyl ether 20; acid amide, amide benzoate, vinegar amides such as toluic acid amide; methylamine, ethylamine,
Amines such as diethylamine, tributylamine, piperidine, tribenzylamine, aniline, pyridine, picoline and tetramethylethylenediamine; and nitriles such as acetonitrile, benzonitrile and tolunitrile. These electron donors
Two or more types can be used.

The quantitative ratio of the constituent components of this solid component is such that the Ti / Mg atomic ratio is 1
× 10 ^-2 to 1 and the halogen / Mg atomic ratio is 0.5 to
An electron donor which is optionally contained in the range of 4
The / Mg molar ratio is preferably in the range of 1 or less.

When silicon, aluminum and boron compounds are contained, these compounds are used in a molar ratio of 1 × 10 ^{−3 to} 100, preferably 1 × 10 ⁻² to 1 with respect to the amount of the magnesium compound used. Is within the range.

The solid component used in the method of the present invention can be produced by a known method. Among them, the following production method is preferable.

(A) A method in which an activated magnesium halide is brought into contact with an electron donor and a titanium compound simultaneously or gradually, in a co-milled or liquid state, to produce the same. to this,
Further, a halogenating agent may be contacted.

(B) If necessary, an electron donor may be added to a precipitate obtained by allowing a halogenating agent, a reducing agent, or the like to act on a magnesium compound in a homogeneous state in the presence or absence of an electron donor. And a method of producing a catalyst by contacting a titanium compound.

(C) A method of producing a catalyst by reacting an organomagnesium compound such as a Grignard reagent with a halogenating agent, a reducing agent and the like, and then bringing the resulting mixture into contact with an electron donor and a titanium compound.

(D) A method for producing a catalyst by bringing a halogenating agent and / or a titanium compound into contact with an alkoxymagnesium compound in the presence or absence of an electron donor.

As the catalyst component (i) used in the present invention, the solid component obtained as described above can be used as it is, or a prepolymerized component obtained by contacting this solid component with an olefin in the presence of an organoaluminum compound. Can also be used. When the component (i) is preliminarily polymerized, the component (ii) is preferably brought into contact after preliminarily polymerized.

When component (i) is preliminarily polymerized, the conditions for prepolymerization of olefins for producing component (i) are not particularly limited, but generally the following conditions are preferred. The polymerization temperature is 0 to 80 ° C, preferably 10 to 60 ° C.
° C. The polymerization amount is 0.00 per gram of solid component.
It is preferred to polymerize 1 to 50 grams of olefins, more preferably 0.1 to 10 grams of olefins.

As the organoaluminum component at the time of the prepolymerization, generally known ones can be used.

As specific examples, Al (C ₂ H ₅ ) ₃ , Al (isoC ₄ H ₉ ) ₃ , A
l (C ₅ H ₁₃ ) ₃ , Al (C ₈ H ₁₇ ) ₃ , Al (C ₁₀ H ₂₁ ) ₃ , Al (C
_{2 H 5) 2 Cl, Al} (isoC 4 H 9) 2 Cl, Al (C 2 H 5) 2 H, Al (isoC
_{4 H 9) 2 H, Al} (C 2 H 5) 2 (OC 2 H 5) , and the like.

Of these, Al (C ₂ H ₅ ) ₃ and Al (isoC ₄ H
₉ ) ₃ . It is also effective to use a combination of a trialkylaluminum and an alkylaluminum halide, or a combination of a trialkylaluminum, an alkylaluminum halide and an alkylaluminum ethoxide.

As a specific example, a combination of Al (C ₂ H ₅ ) ₃ and Al (C ₂ H ₅ ) ₂ Cl, a combination of Al (isoC ₄ H ₉ ) ₃ and Al (isoC ₄ H ₉ ) ₂ Cl, C
₂ H _{5) 3} and _{Al (C 2 H 5) 1} . 5 Cl 1. 5 combination, Al (C ₂ H _{5) 3} and A
Combination of l (C ₂ H ₅ ) ₂ Cl and Al (C ₂ H ₅ ) ₂ (OC ₂ H ₅ ) can be mentioned.

The amount of the organoaluminum component used in the prepolymerization is 1 / Al (Ti molar ratio) with respect to the Ti component in the solid component (A).
-20, preferably 2-10. In addition, a known electron donor such as an alcohol, an ester or a ketone may be added during the prepolymerization.

Examples of the olefin used in the prepolymerization include ethylene, propylene, 1-butene, 1-hexene, 4-methyl-pentene-1 and the like. It is also possible to make hydrogen coexist during the prepolymerization.

Thus, a prepolymerized component (i) in which a solid component containing tetravalent titanium, magnesium and halogen as essential components is brought into contact with an olefin in the presence of an organoaluminum compound is obtained.

Component is contacted with the component (i) to produce a component of the catalyst used in the process of the present invention (A) (ii) is the general _{^{formula, R 1 R 2 3- nSi (}} OR 3) n ( where, R ¹ is a branched hydrocarbon residue, R ² is the same or different hydrocarbon residue as R ¹ , R ³ is a hydrocarbon residue,
n is a number satisfying 1 ≦ n ≦ 3).

Here, R ¹ is preferably branched from a carbon atom adjacent to a silicon atom. In this case, the branching group may be an alkyl group, a cycloalkyl group or an aryl group (for example,
A phenyl group or a methyl-substituted phenyl group). More preferred R ¹ is ^one in which the carbon atom adjacent to the silicon atom, ie, the carbon atom at the α-position, is a secondary or tertiary carbon atom.

In particular, those having a tertiary carbon atom bonded to a silicon atom are preferred. The carbon number of R ¹ is usually 3 to 20, preferably 4 to 10. R ² has 1 to 20 carbon atoms, preferably 1 to
It is usually 10 branched or straight-chain aliphatic hydrocarbon groups. R ³ is usually an aliphatic hydrocarbon group, preferably a linear aliphatic hydrocarbon group having 1 to 4 carbon atoms.

 Hereinafter, specific examples of the silicon compound as the component (ii) will be shown.

_{(CH 3) 3 C-Si} (OCH 3) 3, (CH 3) 3 C-Si (OC 2 H 5) 3 (C 2 H 5) 3 C-Si (OC 2 H 5) 3, etc.

The contact conditions between component (i) (either pre-polymerized or non-pre-polymerized) and component (ii) are as follows:
Any one can be used as long as the effects of the present invention are recognized, but the following conditions are generally preferred. The contact temperature is about −50 to 200 ° C., preferably 0 to 100 ° C.

Examples of the contacting method include a mechanical method using a rotary ball mill, a vibration mill, a jet mill, a medium stirring and pulverizing machine, and a method of contacting by stirring in the presence of an inert diluent. Inert diluents used at this time include aliphatic or aromatic hydrocarbons and halohydrocarbons, polysiloxanes and the like.

Regardless of whether or not the component (i) is preliminarily polymerized, the quantitative ratio of the component (i) to the component (ii) is determined by the atomic ratio of silicon of the component (ii) to the titanium component constituting the component (i) (silicon / titanium).
In the range of 0.01 to 100, preferably in the range of 0.1 to 10.

Component (B) Component (B) is an organoaluminum compound. Specific examples, R ⁷ _3- nAlXn _{^{or, R 8 3- mAl (OR 9}} ) m ( wherein R ⁷ and R ⁸ are identical or different connexion which may number about 20 carbon hydrocarbon residue or hydrogen Atom, R ⁹ is a hydrocarbon residue, X
Is a halogen, n and m are respectively 0 ≦ n ≦ 3, 0 <m
<3. ). Specifically, (a) trialkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, and tridecylaluminum;
Alkyl aluminum halides such as diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, etc., (c) diethylaluminum hydride, diisobutylaluminum hydride, (d) diethylaluminum ethoxide, diethylaluminum phenoxide, etc. Aluminum alkoxide.

These (a) other organometallic compounds with an organoaluminum compound to (c), for example _{^{R 10 3- aAl (OR 11)}} a ( wherein 1 ≦ a ≦ 3, R ¹⁰ and R ¹¹ are the same or different connexion And a hydrocarbon residue having about 1 to 20 carbon atoms.) Can also be used in combination. For example, a combination of triethylaluminum and diethylaluminum ethoxide, a combination of diethylaluminum monochloride and diethylaluminum ethoxide, a combination of ethylaluminum dichloride and ethylaluminum diethoxide, triethylaluminum and diethylaluminum ethoxide and diethylaluminum chloride Are used in combination.

The amount of the component (B) used is such that the component (B) / component (A) is in the range of 0.1 to 1000, preferably 1 to 100 in weight ratio.

Component (C) The catalyst component (C) used in the present invention has a general formula M (OR
⁴ ) Compound represented by xR ⁵ yXz.

Here, M represents an element selected from B, Al, C, Si, P, Ti and Zr, and R ⁴ and R ⁵ represent a hydrocarbon residue having about 1 to 20 carbon atoms which may be the same or different, X represents a halogen atom. Also, x is a number greater than 1 and less than or equal to the valence of M, and x + y + z is equal to the valence of M.

Specifically, the following compounds can be exemplified. Boric esters such as trimethyl borate, triethyl borate, tripropyl borate, and triphenyl borate; diethyl aluminum methoxide, diethyl aluminum ethoxide, diethyl aluminum butoxide, diethyl aluminum phenoxide, diisobutyl aluminum ethoxide, Aluminum alkoxides such as ethylaluminum diethoxide, aluminum triethoxide, aluminum triisopropoxide, aluminum trisec butoxide, aluminum triphenoxide; diethyl ether, diisobutyl ether,
Diisoamyl ether, diphenyl ether, tetrahydrofuran, dimethyldimethoxymethane, diethyldimethoxymethita, diphenyldimethoxymethane, phenylmethyldimethoxymethane, tbutyldimethoxymethane,
Diphenyldiethoxymethane, dimethyldiphenoxymethane, methyl orthoacetate, methyl orthopropionate,
Ethers such as methyl orthobenzoate, ethyl orthobenzoate, butyl orthobenzoate, etc., ketals, orthocarboxylates; tetramethylsilicate, tetraethylsilicate, tetrabutylsilicate, tetraphenylsilicate, methyltrimethoxysilane, methyltriethoxy Silane, ethyltriethoxysilane, octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyl Diethoxysilane, phenylmethyldimethoxysilane, t-butylmethyldimethoxysilane, phenyltbutyldimethoxysilane, norbornylmethyldimethoxysilane Silicates such as phenyl, norbornyldimethoxysilane, trimethylmethoxysilane, triphenylethoxysilane, and chlorotrimethoxysilane; trimethyl phosphite, tributyl phosphite, trioctyl phosphite, tridodecyl phosphite, Phosphorous esters such as trioleyl phosphite, dimethyl methyl phosphite, diethyl methyl phosphite, diethyl phenyl phosphite, ethyl dimethyl phosphite, methyl diethyl phosphite, methyl diphenyl phosphite; tetraethoxy titanium, tetra ethoxy Titanium alkoxides such as isopropoxytitanium, tetrabutoxytitanium, tetra-2-ethylhexoxytitanium, tributoxycyclotitanium, dibutyldichlorotitanium; tetraethoxyzirconium, tetrabutoxy Rukoniumu,
Zirconium alkoxides such as tetraoctoxyzirconium, tributoxycyclozirconium and dibutyldichlorozirconium; and the like.

The amount of component (C) used is preferably in the range of 0.01 to 5 in molar ratio to the aluminum atom contained in component (B).

The component (C) may be used from the beginning of the step (1) of the propylene copolymerization of the present invention, but the component (C) is substantially used in the step (2).
Is preferably added at the end of step (1) in which is carried out, or at the beginning or in the middle of step (2).

(Polymerization) The polymerization step in the method of the present invention performed in the presence of the catalyst comprises at least two steps of step (1) and step (2), and step (1) and step (2) are performed in this order. This is industrially advantageous.

Step (1): In the step (1), propylene alone or a propylene / ethylene mixture having an ethylene content of 5% by weight or less, preferably 0.5% by weight or less is fed to the polymerization system in which the catalyst is present, and one or more stages are used. 60-95% by weight of polymerization amount
This is a step of forming a polymer in an amount corresponding to the above.

In step (1), when the ethylene content in the propylene / ethylene mixture exceeds the above value, the bulk density of the final copolymer decreases, and the amount of low-crystalline polymer by-produced greatly increases.
The same phenomenon occurs when the polymerization ratio is less than the above range.

On the other hand, if the polymerization ratio exceeds the above range, the amount of by-products of the low crystalline polymer decreases, but the impact strength, which is the object of the block copolymer, is undesirably reduced.

The polymerization temperature in the step (1) is 30 to 90 ° C., preferably 50 to 90 ° C.
~ 80 ° C. The polymerization pressure is about 1 to 40 kg / cm ² .

It is preferred to use a molecular weight regulator so that in step (1) the flowability of the final polymer gives favorable results. Preferred molecular weight regulators include hydrogen.

Step (2): In the step (2), following the step (1), a propylene / ethylene mixture having an ethylene content of 20 to 100% by weight is further introduced. % Of the polymer.

If the polymerization ratio in the step (2) is less than the above range, the impact resistance is poor, and if it exceeds the above range, the amount of by-products of the low-crystalline polymer increases significantly, and the viscosity of the polymerization solvent increases to increase the operation. Problem also arises.

In the step (2), another comonomer may coexist. Specifically, α-olefin such as 1-butene, 1-pentene and 1-hexene can be exemplified.

In the step (2), the polymerization temperature is 30 to 90 ° C, preferably 50 to 90 ° C.
80 ° C. The polymerization pressure is about 1 to 40 kg / cm ² .

When moving from step (1) to step (2), it is preferable to purge propylene gas or a propylene / ethylene mixed gas and hydrogen gas before moving to the next step.

In the step (2), a molecular weight regulator may be used according to the purpose. That is, when importance is placed on the impact resistance of the final polymer, it is preferable to perform the reaction substantially in the absence of a molecular weight modifier. On the other hand, when importance is placed on transparency, gloss, whitening, and the like, the molecular weight regulator is used. It is preferably performed in the presence of

Polymerization method: The production of the copolymer according to the present invention is carried out by a batch method,
The method can be implemented by either a continuous or semi-batch method. Further, at this time, a method of polymerizing in an inert hydrocarbon solvent such as heptane, a method of polymerizing using a monomer itself as a medium, a method of polymerizing with a gaseous monomer without using a medium, and further, And a method of performing polymerization by combining them.

Experimental Example Example A-1 [Production of Component (A)] 200 ml of dehydrated and deoxygenated n-heptane was introduced into one flask which had been sufficiently purged with nitrogen.
0.4 mol of gCl ₂ and 0.8 mol of Ti (O-nC ₄ H ₉ ) ₄ were introduced, and 9
After reaction at 5 ° C. for 2 hours, the temperature was lowered to 40 ° C. after completion of the reaction, and then 48 milliliters of methylhydropolysiloxane (20 centistokes) was introduced, followed by reaction at that temperature for 3 hours. After the completion of the reaction, the reaction product was washed with n-heptane. The reaction product thus obtained is referred to as “intermediate-
1 ".

Then, 50 ml of n-heptane purified in the same manner as described above was introduced into a flask sufficiently purged with nitrogen, and 0.24 mol of the above product was converted into Mg atoms. Then, SiCl ₄ 0.4
Mole was added to the flask at 30 ° C. for 30 minutes and reacted at 70 ° C. for 3 hours. After the completion of the reaction, the resultant was washed with n-heptane.

Further, 0.02 mol of triethyl borate is added to n-heptane 25
The solution diluted in milliliters was added to the flask at 70 ° C. for 30 minutes and reacted for another 30 minutes. After completion of the reaction, n
-Washed with heptane.

Further, a solution obtained by diluting 0.016 mol of phthalic acid chloride with 25 milliliters of n-heptane was added to the flask at 70 ° C. for 30 minutes, and the mixture was further reacted for 1 hour. After the completion of the reaction, the resultant was washed with n-heptane.

Finally, 0.24 mol of SiCl ₄ was added and reacted at 95 ° C. for 6 hours, and the reaction product was washed with n-heptane. The solid component thus obtained had a Ti loading of 1.87% by weight.

25 ml of dehydrated and deoxygenated n-heptane was introduced into a flask sufficiently purged with nitrogen, and 5 g of the solid component obtained above and t-butylmethyldimethoxysilane were added so that Si / Ti = 4.5. It was introduced and reacted at 50 ° C. for 90 minutes. After the completion of the reaction, the resultant was washed with n-heptane to obtain a catalyst component (A).

(Propylene copolymerization)

After sufficiently replacing the inside of a 1.5-liter stirred autoclave with propylene, 500 ml of sufficiently dehydrated and deoxygenated n-heptane was introduced, 25 mg of the above-mentioned catalyst component (A) and triethylaluminum (catalyst component). (B)) 125 milligrams were introduced under a propylene atmosphere.

In the first stage polymerization, after introducing 220 milliliters of hydrogen,
At a temperature of 75 ° C., propylene was introduced at a constant rate of 0.932 g / min.

After 3 hours, the introduction of propylene was stopped and the polymerization was continued at 75 ° C. Pressure Samples were 1/10 taken at Natsuta time and 2kg / cm ² gauge, it was to purge the gas phase until the 0.2kg / cm ² gauge.

In the second stage polymerization, after adding 75.6 mg of tetrabutoxyzirconium (component (C)), propylene was added to a concentration of 0.5 g.
0546 g / min and ethylene at a constant rate of 0.218 g / min were introduced at 60 ° C. for 1.5 hours.

After completion of the polymerization, the gas phase was purged, and the slurry was filtered and dried to obtain 155.3 g of a polymer. On the other hand, the filtrate was dried to obtain 2.21 g of a low-crystalline polymer as a by-product. The MFR of the resulting polymer was 2.19 g / 10 min, and the bulk density (BD) was 0.457 g / cc.

The MFR of the polymer obtained by drying the intermediate sample was 5.40 g / 10 minutes.

Example 2, Comparative Example 1 Except for changing the branched hydrocarbon-substituted silicon compound from t-butylmethyldimethoxysilane to norbornylmethyldimethoxysilane and diphenyldimethoxysilane in the production of the solid catalyst component of Example 1, respectively. Is
Production of a solid catalyst component and copolymerization of propylene were performed in the same manner as in Example 1.

 The results are shown in Table 1.

Examples 3 to 5 Production of a solid catalyst component in the same manner as in Example 1 except that tetrabutoxyzirconium as the component (C) was changed to an alkoxy compound shown in Table 1 during the copolymerization of propylene in Example 1. And propylene were copolymerized.

 The results are shown in Table 1.

Example 6 [Production of catalyst component (A)] Intermediate-1 was produced in exactly the same manner as in Example 1.

Next, 25 ml of sufficiently dehydrated and deoxygenated n-heptane was introduced into a flask sufficiently purged with nitrogen, and 0.24 mol of Intermediate-1 in terms of Mg atoms was introduced. Then, 0.4 mol of SiCl ₄ was added to the flask at 30 ° C. for 30 minutes,
The reaction was performed at 90 ° C. for 3 hours. The reaction product was washed with n-heptane.

Further, 0.016 mol of phthalic acid chloride was added to n-heptane 2
The solution diluted at 5 milliliters was added to the flask at 70 ° C. for 30 minutes and reacted for 1 hour.
-Washed with heptane.

Finally, add 5.0 grams of phosphorus pentachloride,
Allowed to react for hours. The reaction product was sufficiently washed again with n-heptane.

The solid component thus obtained had a Ti loading of 1.52% by weight.

500 milliliters of sufficiently dehydrated and deoxygenated n-heptane, 4.2 grams of triethylaluminum, and 20 grams of the solid component obtained above were introduced into a 1.5-liter internal volume stainless steel stirring tank having a stirring and temperature control device. The temperature in the vessel was set to 20 ° C., and propylene was introduced at a constant rate of 0.67 g / min for 30 minutes. The product obtained is n-
Washed thoroughly with heptane. The product contained 0.86 grams of polypropylene per gram of solid catalyst.

Into a flask sufficiently purged with nitrogen, sufficiently dehydrated and deoxygenated n-heptane was introduced in an amount of 50 milliliters, and the solid catalyst containing polypropylene obtained above was introduced in an amount of 5 grams in terms of the solid catalyst, and t-butylmethyldimethoxysilane was added. Si
/ Ti = 3 and reacted at 50 ° C. for 90 minutes. After completion of the reaction, the reaction product was washed with n-heptane to obtain a catalyst component (A).

(Propylene copolymerization)

Using the same apparatus as in Example 1, propylene was copolymerized in the same manner as in Example 1 except that 15 mg of the catalyst component (A) obtained above was used.

 Table 2 shows the results.

Examples 7 to 9 In the same manner as in Example 6, except that the tetrabutoxyzirconium component (C) was changed to an alkoxy compound shown in Table 2 during the copolymerization of propylene, the production of a solid catalyst component and propylene Was copolymerized.

 Table 2 shows the results.

Example 10 [Production of catalyst component (A)] Intermediate-1 was produced in exactly the same manner as in Example 1.

Then, 100 ml of sufficiently dehydrated and deoxygenated n-heptane was introduced into a flask sufficiently purged with nitrogen, and 0.24 mol of Intermediate-1 in terms of Mg atoms was introduced. Next, 0.48 mol of SiCl ₄ was introduced into the flask at 20 ° C. for 30 minutes, and reacted at 50 ° C. for 3 hours. After the completion of the reaction, the resultant was washed with n-heptane.

The solid component thus obtained had a Ti loading of 4.60% by weight.

Using the apparatus for prepolymerizing the solid catalyst used in Example 6, 500 ml of sufficiently dehydrated and deoxygenated n-heptane, 3.8 g of triisobutylaluminum and 20 g of the solid component obtained above were introduced. The temperature in the vessel was adjusted to 15 ° C., and propylene was introduced at a constant rate of 2.0 g / min for 30 minutes. The obtained product was sufficiently washed with n-heptane.
The product contained 2.67 grams of polypropylene per gram of solid catalyst.

Into a flask sufficiently purged with nitrogen, sufficiently dehydrated and deoxygenated n-heptane was introduced in an amount of 50 milliliters, and the solid catalyst containing polypropylene obtained above was introduced in an amount of 5 grams in terms of the solid catalyst, and t-butylmethyldimethoxysilane was added. Si
/ Ti = 3 and reacted at 50 ° C. for 90 minutes. After the completion of the reaction, the reaction product was washed with n-heptane to obtain a catalyst component (A).

(Propylene copolymerization)

Using the same apparatus as in Example 1, sufficiently dehydrated and deoxygenated n-heptane was introduced at 500 milliliters, 15 mg of the above-mentioned catalyst component (A), 125 mg of triethylaluminum (catalyst component (B)), and tributoxy were added. 68.2 mg of zirconium chloride (catalyst component (C)) was added under a propylene atmosphere.

In the first-stage polymerization, after introducing 220 milliliters of hydrogen, the temperature was set to 70 ° C., and propylene was introduced at a constant rate of 0.932 g / min.

After 3 hours, the introduction of propylene was stopped and the polymerization was continued at 70 ° C. When the pressure reached 2 kg / cm ² gauge, 1/10 of the whole was sampled as an intermediate sample. Further, the gas phase was purged to 0.2 kg / cm ² gauge.

In the second stage polymerization, ethylene was added at a constant speed of 0.273 g / min.
Introduced at 0 ° C. for 1.5 hours.

After the polymerization, the gas phase was purged, and the slurry was filtered and dried to obtain 158.3 g of a polymer (catalytic activity was 1
2300 g-polymer / g-solid component (A) (however, the remainder excluding the prepolymerized polymer)]. On the other hand, the liquid was dried to obtain 1.58 g of a by-product low-crystalline polymer. The MFR of the resulting polymer is 2.43 g / 10 min and the bulk density (BD) is
It was 0.490 g / cc. Further, the MFR of the polymer obtained by drying the intermediate sample was 9.80 g / 10 minutes, and the estimated MFR of the two stages was 2.8 × 10 ⁻⁴ g / 10 minutes.

In the above experimental example, the estimated two-stage MFR was obtained from the following equation.

Where A is produced polymer weight, a ₁ from off Eid monomers in one step, single stage polymer product quantity dissolution amount and estimated by subtracting the gas phase gas amount in the solvent of the monomer obtained from the temperature and pressure, a ₂ is Similarly, the estimated amount of the two-stage polymer, MFR-A indicates the MFR of the generated polymer, and MFR-1 indicates the MFR of the one-stage intermediate sample.

[Brief description of the drawings]

FIG. 1 is to assist in understanding the technical contents of the present invention relating to the Ziegler catalyst.

Continuation of the front page (56) References JP-B 8-26094 (JP, B2) JP-B 8-26095 (JP, B2) Patent 2521676 (JP, C1)

Claims (1)

(57) [Claims] 1. A process for producing a propylene copolymer, comprising performing the following steps in the presence of the following catalyst: Catalyst A catalyst obtained by combining the following components (A), (B) and (C): Component (A) Component (i): a solid component containing tetravalent titanium, magnesium and halogen as essential components, and a component (ii): general formula _{^{R 1 R 2 3- nSi (oR}} 3) n ( where the R ¹ is a branched hydrocarbon residue, the R ² is R ¹ identical or different hydrocarbon residues, R ³ is a hydrocarbon residue, n is 1 ≦ n ≦ 3
), A solid catalyst component obtained by contacting a silicon compound represented by the following formula: (B) an organoaluminum compound, (C) a general formula M (OR ⁴ ) xR ⁵ yXz (where M is B, Al, C, Si,
R represents an element selected from the group consisting of P, Ti and Zr, R ⁴ and R ⁵ represent the same or different hydrocarbon residues having 1 to 20 carbon atoms, X represents a halogen atom, and x is greater than 1; An alkoxy compound having a number equal to or less than the valence of the element and x + y + z being equal to the valence of the M element), comprising the following steps (1) and (2), wherein the total ethylene content is 3 to 40% by weight. Step (1): Propylene alone or a propylene / ethylene mixture having an ethylene content of 5% by weight or less is polymerized in one or more stages to produce a propylene copolymer in an amount corresponding to 60 to 95% by weight of the total polymerization amount. And (2) a step of polymerizing a propylene / ethylene mixture corresponding to an ethylene content of 20 to 100% by weight in one or more stages.